The structure of orange peel is complex and has multiple layers of tissue, each with its own unique functions and characteristics. The following are the main structures and characteristics of orange peel:
Exocarp (epidermis)
The exocarp is the outermost layer of the orange peel, mainly composed of polygonal epidermal cells, the outer walls of these cells are keratinized, and the surface is covered with a layer of wax, which has a protective effect. There are also oil cells distributed on the exocarp, which are rich in essential oils, mainly composed of terpenes, sesquiterpenes and their oxidized derivatives, giving oranges a unique aroma.
Misocarp (spongy layer)
The mesocarp is located on the inner side of the exocarp, is white and spongy, has a loose structure, and contains vascular bundles (i.e. orange pith). The main function of this layer is to absorb impact and protect the internal structure of the fruit. When squeezed, the spongy layer will push outward, which may cause the exocarp to crack and spray out essential oils.
Endocarp
The endocarp is the innermost and thinnest layer of the orange peel, which directly wraps the orange segments. The endocarp forms partitions between the orange segments, allowing the orange segments to be closely arranged but easy to separate. The cells of the endocarp swell, vacuolate and eventually die when the fruit matures, leaving behind thin cell walls, which makes it impossible for the orange segments to close again after being torn apart.
Functions and characteristics
Protective function: The wax layer and oil cell layer of the exocarp jointly protect the fruit from external damage.
Aroma source: The essential oils in the oil cells are the main source of the orange aroma.
Buffering function: The spongy structure of the mesocarp can absorb impact and protect the inside of the fruit.
Partitioning function: The endocarp separates the orange segments, making them easy to separate after ripening.
In summary, the structure of the orange peel not only has a protective function, but is also closely related to its aroma, buffering and partitioning properties. If you want to learn more about the chemical composition or functions of orange peel, you can search for orange peel essential oil or orange peel cell structure.
